In radiation therapy using medical radiation therapy equipment, one of the most important factors is to focus radiation to a tumor while minimizing radiation to peripheral normal tissues. In particular, treatment techniques such as SBRT, SRS, IMRT, etc., which are recently introduced, require much higher precision and accuracy than existing 2D and 3D treatment techniques, due to a highly conformal dose distribution to a tumor with sharp dose fall off at the boundary.
Accordingly, quality assurance of the medical radiation therapy equipment has received much attention in the field of radiation therapy. The quality assurance of radiation therapy equipment globally follows recommendations made by the American Association Physics and Medicine (AAPM) of U.S. and the European Society for Radiotherapy and Oncology (ESTRO) of Europe. The quality assurance items in the recommendations are divided into two categories, one is a mechanical quality assurance, which verify the accuracy of geometry and mechanical components of the equipment and the other is radiation dose related quality assurance which assures the accuracy of the radiation from the equipment. The present invention related to the mechanical quality assurance.
The existing mechanical quality assurance methods of radiation therapy equipment use visual verification of the accuracy of three geometry centers which are, a gantry, a collimator, and a couch center while rotating each corresponding part. However, the method does not guarantee the measure in the degree of precision, that is less than 1 mm, required in the special treatments such as SBRT, SRS, IMRT, etc. In addition, the quality assurance results can be differing between measurers evaluating the radiation therapy equipment. In particular, aforementioned quality assurance methods are qualitative which are incapable of producing objective data, and thus, objectivity is very low and improvement is necessary.
Although Korean Patent No. 10-0981781 (Sep. 6, 2010) discloses a technology to improve performance of the existing radiation therapy equipment, there is a demand to develop technologies for an automatic evaluation system and method for quality assurance of radiation therapy equipment.